Plastic T-shirt bags have largely displaced paper bags over the last twelve years in grocery and other major retail markets. One of the major reasons for the market success of plastic bags, aside from their inherent cost advantage, has been the development of racks to manage the thin, flexible and difficult to control bags. Unlike a paper bag that can stand up on its own while being loaded with groceries, plastic bags initially required a packer to hold the bag up in an open position with one hand and load the groceries with the other hand.
The primary function of early plastic bag racks was to hold the bags suspended over a base in an open position, freeing the packer to use both hands to load the groceries. Following these early racks were numerous bag rack designs that improved the speed with which the bags could be opened, packed and removed. Bag racks were developed that could store and accommodate a flat bundle of unopened bags. Opening of the bags was made easier by perforating both arms of each bag handle and suspending the bags from these perforations by cantilevered arms on each side of the rack. The entire bundle of bags could be pre-loaded onto the cantilevered arms and held in place by hooking the bags to the back of the rack. Opening a bag involved simply pulling the front of the bag forward, as the handles slid along the cantilevered arms. Opening of the bags was made easier still by forming a thin film tab at the top center of the bag which enabled the packer to pull the front of the bag forward and open the bag by merely touching and pulling forward on the tab. Further developments led to connection of a succession of the bags at this tab section so that the removal of the first bag from the rack pulled the tab of the next bag, semi-automating the bag-opening process.
For all their advantages and speed in opening bags, however, plastic bag racks still do little more to improve actual packing of the bag than to suspend the bag in an open position. The thin plastic film bags have no inherent structure for supporting items loaded therein. When loaded improperly or in a random fashion, the bags stand up properly and contain the grocery items only for as long as they are suspended from the rack. When they are removed and placed on the counter or in a shopping cart, the sides are no longer supported and, as a result, they slump down as the groceries shift and lean against the thin sides of the bag that offer no support. To prevent this, store personnel typically under-fill the bags to avoid spilled groceries. Lower item counts per bag lead to higher bagging costs and also waste material.
Plastic bags can be packed to the same capacity as a similarly dimensioned paper bag, and still remain stable in transit, but the items must be carefully placed in the bag. The most important step in packing a plastic bag so that it will be stable when filled to the bag's capacity is the placement of the very first items. These items, which are ideally boxes and other wide items, should be placed up against the interior sides and front and back of the bag to "build the perimeter." Then the base or bottom of the bag can be packed with stable or heavy items such as a beverage six-pack, and smaller, lighter items can then be placed on top in the center.
Such a proper packing procedure requires considerable care because the thin, flexible sides of the bag provide no support for the initial items around the bag's perimeter. Items pushed out to the sides of the bag walls will either slip right off the edge of the rack base or not stand up because there is nothing for them to lean against. If the first item does stand up on its own, pushing the next item up against the opposite side of the bag can topple the first item by the next item pulling the bag in the opposite direction.
Packers can be observed compensating for this tendency of the plastic bags by leaving one hand inside the bag to prevent the first items from falling inward and holding space open in the center of the bag, while reaching for and retrieving the next items with the other hand. Packing with one hand not only slows the bagging process, repetitive leaning and reaching can introduce ergonomic hazards as well. Again, plastic bag racks have made very little real progress in addressing the difficulty inherent in packing thin, flexible, difficult to control bags.
Plastic bags can be packed correctly, but the bagger must use care and learn the physical boundaries or limits of both the bag and base of the rack being used by that particular store. Such careful packing of the bags is seldom accomplished. The situation is exacerbated by the youth and high rates of turnover among store employees hired to pack bags. The demands placed on baggers to get customers through the checkout line result in poorly packed, and therefore under-filled bags. Retailers complain about the under filling of plastic bags and the associated costs, and the plastic bag manufactures respond by generating training materials to counteract improper and under filled bags. The stores are sent well-produced printed materials and videotapes to educate store employees on the proper bagging procedure. The success of these campaigns then depends on busy store managers who must schedule, implement and continually reinforce the training program as new baggers are hired. If these training efforts are begun at all, they are typically abandoned in short order due to the sheer volume of people who go through these positions.
The first racks built to suspend plastic bags in an open position were of sheet metal construction. These sheet metal racks had sharp edges and required manual opening of the bag and hooking the loops over pegs or other loop-holding designs. The sheet metal racks were also awkward to unload as the loops of a full bag had to be unhooked from the pegs. Another disadvantage of the sheet metal racks was their tall parallel sides. When a bagger over-filled a bag, the bag would be difficult to remove due to the friction against the opposed side walls. The sheet metal racks were eventually replaced by racks constructed of formed wire with a solid base of sheet metal or a thick thermoplastic.
The first formed wire racks required manual opening of the bag but did not have the sharp edges of sheetmetal racks and provided the strength and durability necessary for continually used dispensing apparatus. A subsequent generation of racks, which are in predominant use today, are also of the formed wire variety and incorporate cantilevered arms to facilitate easy-opening bags. These wire racks, like their predecessors provided strength but required numerous secondary operations to construct.
Each wire rack has many separate sections of wire which must be bent into shape, then cut to length, crimped welded together, ground at the ends and sometimes the welds, chrome plated, and assembled with a base that also has been cut, drilled, etc. The number of secondary manufacturing operations required to construct these racks have made them costly to produce.
Plastic bag companies are typically forced to provide their racks free of charge to their larger customers. Adding to their cost is the fact that they are cube-shaped with parallel sides which makes nesting impossible and can therefore only be shipped and stored two in a box. A typical store will have eight or more checkouts with two or three bag racks per checkout. Thus, cost is a paramount concern.
Yet another disadvantage of the current formed and welded wire racks is the proliferation of alternative plastic bag sizes in recent years. The initial plastic bags were predominantly the same size as their paper counterparts: 1/6th barrel bags. Many retailers, however, concluded that if their plastic bags were being under-filled anyway, why not use a somewhat smaller, less expensive bag: the 1/7th barrel bag. Still other retailers reasoned that a thicker, larger bag would encourage baggers to fill the bags. This led plastic bag manufacturers to introduce the larger, heavy-gauge "big bag." For a bag rack to function properly, it must suspend the bag so that when the bag is fully opened, the gusseted bottom of the bag rests flat on the base of the rack. The proliferation of bag sizes therefore led to a proliferation of rack sizes. Once a wire rack was formed and welded as a unit, it was dedicated to particular bag size. The bag manufactures were thus forced to stock a multitude of finished bag racks and to replace and discard the expensive racks every time a customer switched to a different bag size.
The current bag racks suffer from other deficiencies as well. Many of the bag racks are mounted to the side of the checkout counter rather than placed on top of the counter in order to conserve space for the flow of groceries as an order is processed. Although some racks have been fashioned with height adjustments, most racks are mounted at a fixed height by their backs in perpendicular orientation to the counter. Some are mounted to the counter by the side of the rack. Either way, once mounted, the racks are inevitably too low for some individuals and too high for others. Further, unlike the bag racks placed on top of the counter, the current bag racks are designed to be mounted in way that allows for no adjustment to the angle that is optimum for a particular individual for retrieving and packing groceries from a particular check stand configuration, which vary greatly in design and configuration.
Even if the rack were specifically made for mounting to a particular check stand, the current designs allow no minor adjustments during the course of a workday. When people are required to perform repetitive motions for long periods of time, it is preferable that they are given the ability to make their own adjustments to their workspace, particularly when numerous individuals utilize the same workspace.